There is a lost episode call Dexter's Rude Removal. Dexter wants to make himself more perfect by removing all of his rude qualities using a "Rude Extractor". Dee Dee naturally shows up to unintentionally mess up Dexter's plan, causing both of them to be hit with an unstable beam from Dexter's invention. The beam separates them into good and evil halves, and the evil halves promptly knock their good sides unconscious. Immediately the bad halves start cursing at each other and wrecking up Dexter's lab before going to eat lunch. They continue to curse and act rudely until their good sides wake up. The good sides trap their rude counterparts in the lab, and they head downstairs to find their mother with a bar of soap, presumably to wash out her kids' mouths with.

This episode was only shown during select animation conventions and was never aired on Cartoon Network due to excessive profane content and language. It has been searched for by fans for years. There are rumors that the episode no longer exists.

So Adult Swim has been trying for a while to get this aired, as per wrangling the permission/rights from Cartoon Network, and they've finally been successful! Today, the censored version of the episode has been uploaded onto Adult Swim's Youtube account in 1080p! No news yet if they're going to air it on TV or even get the uncensored version up (if a production version exists), but this is incredible. As the common reaction seems to be, it's like watching an old episode as if it were brand new. It has all the likenesses of classic Dexter episodes, except this time with some swearing. Nothing too odd, right? Erm... right?